波瓣凹扇修形对波瓣强迫混合排气系统性能影响

依据某型涡扇发动机波瓣强迫混合排气系统结构,保持波瓣数以及波瓣几何参数不变,改变波瓣尾缘的凹扇修形程度,从而获得一组除凹扇修形程度不同其余几何参数均相同的波瓣几何模型。对该涡扇发动机波瓣强迫混合排气系统采用三维CFD模拟的方法,得到了凹扇修形对涡扇发动机波瓣强迫混合排气系统气动热力性能的影响规律。研究结果表明:在波瓣尾缘以及混合排气系统出口,随着凹扇修形程度的变大,热混合效率均呈现出上升的趋势;而总压恢复系数则均逐渐地减小。在混合排气系统出口,推力混合效率随凹扇修形程度的变大而上升,与没有凹扇修形的模型相比,研究的凹扇修形模型的推力混合效率最大增加了39.33%。此外,随着流向涡沿轴向发展,波瓣凹扇修形对热混合效率的影响逐渐减弱。

Effect of elliptical cut at trailing edge of a lobed mixer on aerodynamic and thermal performance of a turbofan forced mixing exhaust system

A series of geometric models only with gradual variation of the level of the elliptical cut at the lobe rear edge of a base lobed mixer were created in the forced mixing exhaust system of a turbofan engine when the lobe number and the lobe geometric parameters were kept unchanged. By the usage of three-dimensional CFD simulation, the effect of elliptical cut at the lobe rear edge on the performance of the forced mixing exhaust system was acquired. The results indicate that at the trailing edge of the lobe and the exit plane of the forced mixing exhaust system, the thermal mixing efficiency rises as the area of the elliptical cut increases, while the total-pressure recovery factor decreases in the meantime. When the area of the elliptical cut increases, the thrust mixing efficiency at the exit plane rises. Compared with the primitive model, the thrust mixing efficiency of the models with the elliptical cut has maximumly increased by 39.33%. In addition, with the development of the streamwise vorticity, the influence of elliptical cut on the thermal mixing efficiency weakens.